Image sensor chips have been widely implemented in everyday lives such as cellular phones, personal digital assistants (PDA), digital still cameras (DSC), digital video cameras (DV), video phones, video conferences, and so on. It is necessary to packaging image sensor chips prior to surface-mounting. A disclosed image sensor package and its packaging method are revealed in R.O.C. Taiwan patent publication No. 459,355. An image sensor chip is flip-chip bonded to a glass substrate. A plurality of signal input terminals and a plurality of signal output terminals, which are formed on the different surfaces of the glass substrate, are electrically connected to each other by traces on surfaces and sides of the glass substrate. The signal input terminals are electrically connected to the image sensor chip and the signal output terminals to a printed circuit board having an opening. Therefore, the electrical transmission path is from the image sensor chip through the glass substrate to the printed circuit board so that the glass substrate possesses two basic criteria, good optical transparency and double-side electrical transmission. However, it is very difficult to fabricate traces on double layers and sides of the glass substrate. Accordingly, the fabrication cost of the glass substrate is very high. Moreover, the image sensor chip is lack of protection.
Furthermore, another known image sensor chip is revealed in R.O.C. Taiwan patent publication No. 484,237, entitled “An optical device with a tape packaging type”. An image sensor package with TCP type includes an image sensor chip, a flexible circuit board, and an encapsulant where the flexible circuit board has a plurality of inner leads and a device hole. The encapsulant accommodates the image sensor chip and has a cavity aligned with the device hole of the flexible circuit board and a sensing area of the image sensor chip. In order to avoid the image sensor chip from the damages of moisture or dusts, a transparent cover is needed to adhere to the sidewall around the cavity. However, the encapsulant is made by molding and its thickness is much greater than the thickness of the flexible circuit board. The sensing area of the image sensor chip is easily contaminated during molding the encapsulant and the total thickness of the image sensor package cannot be reduced.